Means for adjusting tachometers for temperature compensation.



v 0.- H. WARNER. MEANS FOR ADJUSTING T AGHOMETERB FOR TEMPERATURECOMPENSATION.

APPLICATION FILED MAY 22, 1911. I

Patented Feb. 25; 1913.

tt aia/{W "TE sratrns PAEENT OFFICE;

' CHARLES- H. WARNER, 0F 'BELOIT, WISCONSIN, ASSIIGNOR T0 WARNERINSTRUMENT COMPANY, OF BELOIT, WISCONSIN, A CORPORATION OF ILLINOIS.

MEANS FOR ADJUSTING TACHOMETERS FOR TEMPERATURE COMPENSATION.

To all whom, '1' i may concern Be it'known that 1, CHARLES H. WARNER,

a citizen of the United States, residing at Beloit, county of Rock,State of WVisconsin,

- have made a certain new and useful Invention in Means for AdplstlngTachometers for Temperature Compensation.

The invention relates generally to devices of the class known astachometers, and particularly, to speedindicating devices, such forinstance, as are employed in connection with automobiles, to indicatetheir speed of travel.

The object of the invention is to provide means which are simple andetlicient for antomatically compensating instruments of the classreferred to for temperature variations, whereby to secure accuracy ofspeed indications at different atmospheric temperatures, and morespecifically stated the" object is to provide simple and etiicient meansfor automatically varying the strength of a rotating magnetic field, theinfluence of which field is utilized to impart movements to the movablemember of a scale and pointer mechanism or other indicating means.

Other objects of the invention will appear more -fully hereinafter.

The invention consists substantially in the construction, combination,location and relative arrangement of parts.'all as will be morefully-hereinafter set forth, as shown in the accompanying dra 'vving,and finally pointed out in the appended claims.

Referring to the accompanying drawing, Figure 1 is a view partly incentral longitudinal section, on the line 1 1, Fig. 2, parts broken out,showing a form of speed indicating device to which my invention isadapted, and showing the application there to of a construction ofatmospheric temper: ture variation compensating mechanism em bodying myinvention. Fig. {2 is a top plan view of t-he same, parts broken out andparts removed to more clearly disclose the con-- struction and relationot parts.

In the manufacture of speed indicators it has been the custom to:ldjllSt the parts to give accurate readings thereof at a normal Forordinary purposes mean I temperature. of use-0t instruments so adplstcdtlus is usually sutlicient since variations in indica-.

time due to changes in atmospheric tem- Specification of Letters Patent.Patented Feb, 25, 1913,

Application filed May 22, 1,911. Serial-No. 628,718.

ordinarily quite small. It may sometimes however, be desirable, in ordertosecure greater accuracy, to make compensating adjustment for even thesmall variations of means of an associated scale and point-er'or hand.one of these parts usually being fixed and the other arranged to bedisplaced relatively thereto, and proportionally to the speed to beindicated. that is. said parts are usually arranged to be relativelydisplaced proportionally to'the speed to be indicated. The displaceableor relatively displacea'ble member ordinarily held yieldingly in aninitial or zero position and'is relatively displaced ormoved from suchinitialposition against the action of a hair or other spring. The meansfor effecting the rotative or relative displacement of the movablemember of the scale and pointer mechanism may be varied throughout awide range, and various constructions, mechanical, centrifugal, as wellas magnetic, are at, resent on the market for accomplishing tiis result.VI have shown my invention as applied to a speed indicator of themagnetic type, that is. of the type in which the movable element of thescale and pointer device is displaced by means of a rotating magneticfield. In the magnetic type of instrument the movable member of thescale and pointer device is ordinarily associated with a disk, cup orother convenient form of device or member, arranged within the influenceof the. rotating magnetic field, and is of such material as to' beinfluenced and rotativcly displaced, against the action of a hairspring, by the magnetic drag; exerted thereon of the rotating field.ducing the rotating magnet field. are embodied in instruments now on themarket. ll'hilc, therefore, I have shown and will no u" describe oneform of means for accomperature, from a meanv temperature, are Iplishing the desired results my inventionyas Various arrangements forpro-- to employ a thermostatioor other device capable of beinginfiuencedby variations inrestricted to this particular arrangement.

defined in the claims, is not to be limited or 11, havin at its free enda pin, 1'2. ar

In carrying out 1ny"invent.ion, I I propose atmospheric temperature, andto employ movements of the thermostatic device, ,due.

- to variations in atmospheric temperature,

to efiec'tcorresponding variations .in the. strength oftherotatingmagnetic field, and in proper-relation to the variations inatmospher-ic temperature.

In the thawing A, designatesa casing in which is mounted to rotate acarrier B, oar- }ryingn magnet (hi'otation being imparted to-the magnetcarrier by' suitable -connec-' tions, and-in the ordinany manner, 'With'thef shaft, or other part the speedof which is to be indicated.ooperat-injgj iththe magnet is a member 'D which iso't'n'iagneti-cmaterial and which. constitutesa' magnetic mass or field ring, thefunction of which is to concentrate the ,lines of force in the inagnetiofield or lair-gapspace between the net 6.. The member D, is arrangedwithin same and. the magnet. In the form shovvn,

the member D, is-siipp'orted forvmovement bodily toward and from therotating na the casing A, a nd is suspended therein'vby means of spr ngsE, or other yielding sup ports, and IIIiQIPQSQd between the magnet 'C,and the mass D,or in suchrela'tion there-.

fill-"25 to be influenced by the lines of orce of the magnetic.- fieldmaintained between ,saidmagnet' and mass, is a member G, carried by aspindle H jOiHIIQlGCl in suitable bearings, and which member Gr,- in thepres ent- :instance,constitutes the rotative' or art of the scale andpointer \m echi the instrumen. 'This movable scale member G, is normallyheld ,in an initial or zero positionby means. of a hair.

spring J, which is connectedtat-one'end to e spindle H and at theotherend to a fixed arm K, forming part of a. ring L, station 'arily -mountedwithin the casing, ,The spring is soconnect-e d with reference to thespindle H as to y'ie'ldingly resist the rotative movement in onedirection ofthe spindle. J ,i

Arranged within the casing is a thermostatic device indicated at 10,that is, adevice which is sensitive t temperature varistatic device isarranged ations, and which, inhe particular construction shown, c'omrisesv a th'ermo-pile' consisting of associated split rings of metalshavi'ngdiif'erent heatcoefficients or different expansivecharacteristics. This -thermo- 'n such relation that the ends thereofapnroachi or recede rom each other under the action of vari-i Conto movewith the thermos tatic when so moved. under- 'varia tions of atmospherictemperature, is-fan arm ranged to be received ,in a recess inthe Asshown, the arm ;11,-c.\'- substantially tangential relatioir to thecircle of the thermostatic device;

and consequentlyunderthe influence ot'the movements thereof, impartedthrough variations n atmospherlc temperature, thefie-ld ,ring or'mag'netmass D, shifted rotatively or in angular direction'relative.to' thegeometric axis thereof. The spring supports E, for. this 'fi'eld'ringfor niass permits such shifting, movement thereofl. Liliks l3, are

pivotally connected at their respective ends to ears 1% 1 5,respectively formed on'th-e supporting ring L, a nd"thefield ring ormass Normally these arms "or linksflS "occupy vertically inclinedpositions, that' 'is,

the pivots of their upper ends are out of vertical line, normally withthlepivots of their lower 1lfilS.' The-supporting ring" L, being fixedand the field, ring or massD,

being shifted rotarily a io'ut its geqanetric axis, 1t will bereadilyseen that the mag netic mass or ring" D, is thusaxially-shifted 'thetendency is for the links 13, to assume position at right angles to theplane ofthe supporting rlng L, that 1s, for. a: line 10inmg the pivots0t lar relation to the plane of said ring L. The

resultcf this action is for the field ring m" disk D to be shiftedautomatically toward and 'from the inagnet C, the bodilyshiftingmovement of said ring toward the magnet Q, being 'yleldinglyresisted by the springsE.

In the manner above described't-he strength the respective ends thereofto approachor recede from 'right 'angjwof the rotatin'ginagnetic' fieldis i automaticallYvaried in accordance with variations in atmospheric;temperature. I .ivhile I have shownand described my invention as appliedto a11'" aut.omobile speed indicating device, I do not- ,clesi1'e. to bel'imitedor. restricted in respect to this particular use thereof, as itis obvious that myuse in connection with instruments ,used for'other'purp oses.

.Having now .set forth the'object and .iia-

'ture of" my invention and' a construction embodying the principlesthereof, what I clalm as new'and usefu'l'and-of my ownin- -magneticlfield, a m mber arranged pvitlnn "thereby, a thermostatic device, meansforconnecting said thermostatic device .t'o one of the 'meinbers of theconcentrated field creating means'to shift the same-rotatively 11invention may .be equally well adapted for according to variations inatmospheric temperature, and, a link conn'ect'edto saidro-.:tativelydisplaceable member and operating to shift the same, whenrotatively displaced, to vary the strength of the rotating magneticfield.

2. Ina tachometer the combination with means for creating a concentratedrotating magnetic field, a member arranged within the influence of saidfield to be displaced thereby, a thermostatic device, means forconnecting said device to one of the members in the rotating fieldcreating means, to

' shift the same rotatively according to varia tions in tem erature-,and a pivoted link connected to said rotatively displaceable memher andoperating to move the same, when rotatively displaced, in a direction tovary the strength of the magnetic field.

'3. In a tachometer the combination with said device and said mass torotatively displace the same according to variations in atmospherictemperature.

. 4. In a tachometer the combination with means for creating aconcentrated magnetic field including a rotatable magnet and a rotat-ingmagnetic mass, :1 scale member arranged-wlthin the influence of saidfield" to be rotativ ely displaced thereby, asupportingmember, means forsupporting said mass therefrom for movement toward and'from the magnetand also for axial rotative movement, a thermostatic device, meansconnecting-sald device to sald mass for rotatlvely displacing the sameaccording to atmos pheric variations, and links respectively connectedpivotally tosaid mass and supporting member. v

In testimony whereof I have hereunto set my hand in the presence of thesubscribing witnesses, on this 25th day of April A. D.,-

CHARLES H. \VAR-NER.

\Vitnesses:

H. \V. Amns, Epwanu M. 'Inoausox.

